MICROVASCULAR PATHOLOGY IN THE SKELETAL-MUSCLE PARANEOPLASTIC PHENOMENON

An electron microscopic investigation was made in order to study capil lary alterations in the muscle paraneoplastic phenomenon associated wi th different malignant rumours. Several abnormalities were found inclu ding basement membrane widening and lamination, endothelial hypertroph y, a varied degree of lumen occlusion, and proliferative changes in pe ricytes. A degenerative process leading to capillary necrosis was also observed. A mononuclear cell infiltrate formed by macrophages, lympho cytes and mast cells was seen. The capillary changes observed suggest the existence of an autoimmune vascular factor in the etio-pathogenesi s of muscle damage in this phenomenon.